Safety device for elevator-cars



1. HOFFER. SAFETY DEVICE FOR ELEVATOR CARS.

APPLICATION FILED MAR. 8. 1920.

1,396,753. Patented Nov. 15,1921.

2 SHEETS-SHEET 2.

FIB.I

l6 %//7 WITNESSES mvsmon corresponding to PATENT OFFICE.

JOHN norrna, or MARIANNA, PENNSYLVANIA.

SAFETY DEVICE FOR ELEVATOR-CARS.

Specification of Letters Patent.

Patented Nov. 15, 1921.

Application flled March 8, 1920. Serial No. 364,055.

To all on ham it may concern Be it knownthat I, JOHN Horrnn, residing at Marianna, in the county of Washington and State of Pennsylvania, a subject of the former Hungarian Kingdom in the former Austro-Hungarian Empire, have invented or discovered certain new and useful Improvements in Safety Devices for Eleva tor-Cars, of which improvements the following is a specification.

My invention relates to improvements in safety devices for elevator cars. Its objects are implicity and effectiveness.

The particular kind of safety device to be preferred will depend in some degree on the nature of the installation. In Letters Patent No. 1,324,451, granted December 9, 1919, I have/shown and described a safety device operati g by springs borne by the car itself; and a device such as that is preferable where it is amatter of importance to keep the shaft as free of cables as possible. The device which I now am about to describe and claim involves the use ofan extra cable, and it 1sat the sametime effective in service. It relates itself particularly to elevators in which the torque exerted by the loaded car upon the car raising and lowering drum isbalanced,in part at least,.by a counterweight. This counterweight, a necessary part of the installation, I find convenient, as a source of power to operate, when the emergency arises, my safety devlce.

The invention is illustratedin the accompanying drawings. Figure I isa view in side elevation showing diagrammatically the essential parts of an elevator installation, and wit-h my presentinvention applied; Fig. II is a view to larger scale, a transverse section on the lane indicated by the dotted line II-II, ig. I; showing in plan the gripping members ofthe safety device, with certainof the ogerating arts, Fig. III is a 1 II, s owing a variation I5 is a fragmentary view Fig. I and illustrating a variation in another feature; Fig. V is a view corresponding to Fig. I, and showing view similar to 1 1n detall; Fig.

an elevator to which my invention in an- .50

other form is applied; Fig. VI is a view in transverse section on the. lane indicated by VII is a view of the gripping members andthe immediately connected parts,of the structure shown in Fig. V, seen in plan from below-that is it is a view in section on the line VII-VII,

but looking upward; and Fig. VIII is a view in section of a detail, on the plane of section not necessarily, placed at the bottom of the elevator shaft. The particular position of drum 4 will be such as, in the particular installation, is convenient. A counterweight 5 hung on a cable 6 exerts upon drum 4 a torque in opposite direction, balancing more This counterweight 5 may if convenientrise and descend 1n the same shaft with car 1,

or in another shaft. This too is a matter determined accordin to circumstance; 1n

somecases, it is preferred to employ, not a weight 5 as such, butto hang two cars in counterbalance, so that each serves as a counterwelght for the other, relieving the drum of excessive torque.

The safety stop device (and I shall first describe that shown in Figs. I, II, and III) includes immovable members, which conveniently take the form of posts extending adjacent the path of car travel. The guides 3 may serve as such posts. Cooperating with such immovable members is a post-engaging device borne. by the car, normally inactive, but upon the parting of the car-sustaining cable brought lnto action, to engage the immovable members and stop the car. This post-engaging device is, according to my invention, brought into action with the aid of "the counterweight.

In the form, shown in Figs. I-III, the car 1 carries a rotatable shaft 7, and to this shaft, or (as will ordinarily be the case) to a drum 8 mounted integrally upon shaft 7, a cable 9 is secured. This cable 9 extends over a sheave at the upper end of the elevator shaft, and is connected to the counterweight ,5, after such manner as is shown, to the end that when cable 2 breaks, the

weight of counterweight 5 and the weight of car 1 will exert opposite pulls upon cable 9. Normally cable 9 runs freely over the sheaves which carry it, and it exerts no appreciable. tension upon drum 8. But in case the main cable breaks, then the opposite pulls just indicated will effect turning of drum 8 and shaft 7, and will by such turning or less completely the torque of the car.

effect operation or the safety device. I-Iere, as elsewhere, the term counterweight 5 will be understood to include another car in counterbalance with the car carrying the safety device.

The safety device may conveniently consist of a pair of post-engaging members 10, arranged on opposlte sides of posts 3. These two members are articulated together by shafts 11, which rotating cause the members 10 to approach one another. This may conveniently be done by screw-thread connection, the threads being so cut that as shafts 11 turn in onedirection or the other members 10 will approach or recede from posts 3. Rotation is imparted to shafts 11 from shaft 7 in either of the ways shown: Fig. II shows beveled-gear connection; Fig. III shows sprocket-chain connection.

Provision should be made, to relieve drum 8 of the torque which otherwise would be exerted, when the car rises to the top of the shaft, by the weight of cable 9 hanging from its guiding sheaves. In Fig. I an arm 12 is shown, pivotally mounted on car 1, and at one end engaging a stop on cable 9. Swinging of arm 12 is resisted by a spring 13. The proportioning of parts is such that spring 13' will sustain the weight of cable 9, and under all normal conditions arm 12 will relieve drum 8 of tension; but upon the great pull exerted upon cable 9 in case cable 2 parts, then spring 13 will be insufiicient; arm 12 will swing aside, compressing. spring 13 as it swings, and the tension then exerted upon cable 9 throughout its length will come upon drum 8 and turn it.

An alternative device is shown in Fig. IV, where a short length of relatively weak line 14 holds slack the end of cable 9 adjacent drum 8. The line 14 is strong enough to carry the weight of cable 9; but it is so weak that when, upon the parting of cable 2, heavy straincomes upon it, it breaks; whereupon the strain then comes upon drum 8. v

The structure of Figs. V, VI and VII requires but a few additional words of explanation. The posts here become T irons 3 arranged as shown; the post-engaging members become jaws 10% pivoted one to another, .after the manner of pairs of shears the remote ends of the shear arms are pivoted to blocks 15 screw-threaded on shaft 11 and shaft ll is turned through beveled gears from the sheave 8 around which the end of cable 9 is coiled. The sheave 8 is borne on a vertical shaft 7% instead of on ahorizontal shaft, as in Figs. I-III. The provision for normally relieving the safety device of the weight ofthe connected cable is as particularly shown in Fig. V that of Fig. IV, ratherthan that of Fig. I. It is obvious that either of these alternateprovisions might "be employed, as the engineer might prefer.

. I; F ig.. VII shows means for releasi ig the safety device after it has functioned and when, as may be assumed, the broken cable 2 has been replaced, and normal conditions are to be reestablished. The releasingmeans consist of a pinion 16 turned by a handle (which may be removable) 1T meshing with pinion teeth on the under side of sheave 8. in equivalent releasing device may be applied to shaft 7 of Figs. II and III.

Regardless of the particular form which the safety device may assume, a pair of cooperating stop members 18 and 19 may be provided borne, the one on rope 9, the other on a stationary part of the structure, coming into engagement when the car reaches or passes beyond the lower range of normal travel, and effective by such engagement to operate the safety device, and to prevent descent of the car to the very bottom of pit or cellar, even though cable 2 be not broken.

The safety device as shown in Fig. I is arranged on the top of the car; as shown in Fig. V it is beneath the floor. It will be understood that either arrangement is permissible for either form of device. Local conditions will dictate, which arrangement is chosen.

In normal operation of the elevator the safety device is inactive; cable 2 parts and car 1 begins to fall that the device becomes active. Then whatever device may be present to relieve the safety device of any strain is swept aside, the opposing pulls of weight 5 and of the falling car come upon cable 9, and through it upon drum 8 (or equivalent sheave 8). The turning of this member brings the pairs of members 10 (or 10") oppositely into engageinent with posts 3 (3 The impelling force tends to draw these members into tighter and tighter engagement with the posts, and so the falling of the car is checked or stopped.

I have described the invention in its application to such an elevator as is used in buildings and in mine shafts. It will be understood that it is applicable to elevator cars or cages of all sorts, in whatever location, whether moving vertically or on an in- I cline.

In the ensuing claims I define the features essential to the practice of my invention. Beyond these essential features, the showing of the drawings is exemplary merely, and modifications in structure and arrangement are permissible.

I claim as my invention:

1. In an elevator installation the combination of a car, a car-operating drum, a

car-sustaining cable connecting car and drum, a counterweight exertingupon said drum a torque opposite in direction to that exerted thereon by said car, a second drum borne by said car, a normally slack .3 1

it is only when connecting said counterweight and said second drum, a safety device borne by said car, and operative connection between the aforesaid second drum and said safety device,

substantially as described.

2. In an elevator installation a car sus' tained by a cable and movable in predetermined path, and a safety device including a post extending adjacent the path of car travel, a safety cable extending from the car longitudinally of the path of car travel, and post-engaging apparatus borne by the car, said post-engaging apparatus including a sheave upon which the safety cable is coiled, said sheave being provided with pinion teeth, and a pinion capable of rotation at will engaging said teeth, substantially as described.

3. In an elevator installation, the combination of a car, a car-operating drum, a carsustaining cable connecting car and drum, a counterweight exerting upon said drum a torque opposite in direction to that exerted thereon by said car, a safety device borne by said car, a safety-device cable connecting safety device and counterweight, and means rendered ineffective on the parting of the car-sustaining cable normally relieving the safety device of the weight of the safetydevice cable, substantially as described.

4. In an elevator installation, the combination of a car, a car-operating drum, a can sustaining cable connecting car and drum, a counterweight exerting upon said drum a torque opposite in direction to that exerted thereon by said car, a safety device borne by said car, a safety-device cable connecting safety device and counterweight, and a member of relatively small tensile strength connecting safety-device cable to car and normally relieving the proximate end of the safety-device cable of strain, substantially as described.

In testimony whereof I have hereunto setmy hand.

JOHN HOFFER.

Witnesses:

J. BLAINE WISE, MRS. EMMA Bn'r'rs. 

